The all-Republican lobby shop Clark Lytle Geduldig & Cranford, which has grown dramatically in recent years, is adding a new partner to kick off the new year. Mike Nielsen, who spent 16 years working on banking and financial services issues as a Senate aide, is joining from the Bennett Group, the firm of former Sen. Robert F. Bennett, R-Utah.

“He has mentored a generation of Republican staffers and been a trusted advisor to me,” the former senator said of Nielsen in a statement emailed by Clark Lytle.

Nielsen advised Bennett on the Senate Banking Committee and worked on legislation including the Gramm-Leach-Bliley Act and the Dodd-Frank financial overhaul law.

Clark Lytle Geduldig & Cranford is on track to post more than $4.8 million in lobbying revenue for 2012, up from $3.6 million in 2011 and just $1.9 million 2010. Its growth is notable because many of K Street’s firms have hit flat stretches in the past two years.

Clark Lytle’s recent clients include the American Institute of CPAs, Boeing Co., the Electronic Payments Coalition, General Motors Co., Koch Industries, MasterCard International and the Children’s Hospital Association, among others.

“He is steady, hard working and respected by everyone he’s ever worked with,” Clark added. “We know our clients will be impressed.”

Clark Lytle Geduldig & Cranford has connections to House GOP leadership, and the firm’s partnership donates generously to Republican coffers. But Nielsen will give the shop’s clients deeper reach into the Senate. He has ties to Utah’s Sen. Orrin G. Hatch, who will play a major role in the coming tax debates as ranking member of the Finance Committee.

“Members like them and staffers trust them,” said Chad Kolton, a partner at HDMK, which has shared clients with Clark Lytle. “Nielsen will add new relationships and different experiences.”

In 2007, Clark, who opened the firm 13 years ago from his native Ohio, brought on Gary Lytle, who was interim president and CEO of the U.S. Telecom Association, and Sam Geduldig, a former GOP leadership and Financial Services Committee aide. In 2011, the shop added Jay Cranford, who was an assistant for policy to Speaker John A. Boehner of Ohio. And that same year, former Rep. Deborah Pryce, R-Ohio, affiliated with the firm.

“They punch way above their weight,” said Tim Keating, Boeing’s top lobbyist, in a statement.

Healthy Boost of Business

Another growing shop, Thorn Run Partners, has added new partner Billy Wynne, a top health care lobbyist who previously worked on the Senate Finance Committee as health policy counsel for Chairman Max Baucus of Montana.

Thorn Run was started in 2010 by Democrat Andy Rosenberg and Republican Chris Lamond. With Wynne, the shop is up to 10 senior lobbyists.

“I’ve known some of the partners there for quite a while, and I think we have kind of a common vision around what consulting and lobbying looks like in the health care space,” Wynne said of his decision to join Thorn Run from Health Policy Source Inc. He previously also worked at Patton Boggs.

He declined to name any clients he might bring to the firm, but said he has a robust book of business and expects to bring on new clients as well. He also plans to bring a team to Thorn Run. The firm’s clients already include the Long Term Care Pharmacy Alliance, Novartis, the Medical Device Manufacturers Association and NISH, a nonprofit that links Washington with contractors that employ disabled workers.

Wynne expects 2013 to be a busy year, especially as Congress and the White House eye changes to such entitlement programs as Medicare and Medicaid and with final implementation of the Affordable Care Act on the horizon. “There are a lot of opportunities and some concerns,” he said.